(You will be looking for stock aluminum when you shop for this material.  Purchase two 3-foot lengths of aluminum L-stock, with 1-inch sides. You will also need a one foot long piece of 1" wide flat aluminum stock, 1/8 inch thick.  You should be able to get the front section and one side of the motor mount assembly from a 36" length of 1" L-stock.  You can cut the second side section from the other 36" bar and use the left over for the back end piece.)

Shopping List
2 ea 36" stock aluminum L-bars (1" sides)
1 ea 12" stock aluminum 1" flat bar
3 ea small, smooth operating pulleys
1 ea small U- bolt, available as a component of a wire clamp kit (such as Campbell part 767-5117 - a kit intended for 3/16" size wire) small enough to encircle the motor's output shaft
1 1/2 inch long 1/4 inch diameter bolts and eyebolts to assemble the motor platform
~30 feet of small diameter rope that will fit loosely in the pulleys
Nylon twine to serve as the lines securing the pulleys to the motor rig.
~ 15-20 feet of Nylon monofilament or fishing line. This will lead from the thicker ropes
required for the pulleys to your marionette.
6 full coat hangers, for the figure's armature beneath the head assembly

Cut Parts List
1 ea of 16"  Aluminum L-bar for front section
2 ea of 20"  Aluminum L-bar for motor mount section
1 ea of 12"  Aluminum Flat bar for the marionette crank